The present invention generally relates to an electromechanical actuator system for use in vehicles, and more particularly to improvements in such systems in connection with a bomb rack (or bomb shackle) release device of the type disclosed in U.S. Pat. No. 2,776,570 and U.S. Pat. No. 3,364,752.
It is well known that high frequency (over 100 MHz) electromagnetic interference (EMI) can adversely affect the performance of electromechanical devices. Bomb rack actuator systems in aircraft are especially vulnerable to high frequency EMI because of their close proximity to other airborne avionic equipment, such as radar and UHF communications gear, that emits high frequency EMI.
In addition to being susceptible to electromagnetic interference, bomb rack actuators also emit high frequency electromagnetic radiation (over 1 MHz) that can adversely affect the performance of other electrical components in an aircraft, such as the radar system, scanning devices, and the guidance system. The effect of high frequency EMI on these devices is particularly acute because of their close proximity to the bomb rack actuator.
In the prior art, the only effort to suppress electromagnetic emissions from bomb rack actuators consists of grounding the actuator switch to the aircraft. This measure, however, does not satisfactorily suppress high frequency electromagnetic emissions for all applications.
The prior art also attempts to shield bomb rack actuator systems from high frequency EMI. These efforts may include one or more of the following: using ordinary coaxial wire to connect the bomb rack actuator to the source of its control signals and to other devices; either winding the metal braid at the end of the coaxial wire into a pigtail and screwing it to something that was grounded or securing the ends of the braid at both the switch case and the connector plug with rubber; enclosing the connector plug in a plastic shell for electrical insulation; and placing the switch in an aluminum container. Although these measures provide some shielding effect, they do not provide, either alone or in combination, suitable high frequency EMI protection for all uses.